The invention relates to a method of obtaining a tomographic image of part of an animal or a part of an animal including a human being or a part of a human being by using radioactive radiation, wherein the animal is at least partly placed into a measuring cavity, the measuring cavity being at least partially surrounded by a cavity wall which is provided with a plurality of pinholes, and wherein behind the pin holes (as viewed from the measuring cavity) detection means are placed, radioactive radiation from a radioactive isotope administered to the animal is detected in a position-related manner by the detection means and data obtained with the detection means are used for the generation of the tomographic image.
The invention also relates to an apparatus for obtaining a tomographic image of a human being or part of a human being or an animal or a part thereof using radioactive radiation, which apparatus comprises a measuring cavity having an axial axis, a cavity wall which at least partly, surrounds the measuring cavity which cavity wall is provided with a plurality of pinholes, the apparatus further comprising detection means which viewed from the cavity, are provided behind the pin holes, wherein the detection means are arranged for receiving, in a position-related manner, the radioactive radiation emitted within the measuring cavity and wherein the detection means can be read electronically or optically.
Such a method and apparatus are known in the art for making tomographic images of animals, including humans, revealing a biological activity (in the case where a compound comprising an isotope to be measured is bound or metabolised) or giving an indication of which locations an isotope can reach. The detection means is a position-sensitive detection means which detects the radiation which falls on the detection means wherein the detection means also registers the position on the detection means which receives the radiation. In other words the radiation is detected in a position related manner. The detection means may also detect the strength (energy of the photons or other radiated particles) of the radiation which is detected on a certain position.
There is need of a method providing a more sensitive way of measuring. This would either allow a reduction of the load of radioactive material used for measuring the animal, or it would allow a biological measurement as described above to be carried out with more precision. There is also a need for measuring at a higher resolution. These requirements of greater sensitivity and higher resolution are in part conflicting.